An abdominal aortic aneurysm is an abnormal enlargement or “ballooning out” of the arterial wall of the aorta in a region that passes through the abdominal cavity, usually below the renal arteries and above the common iliac arteries. The aneurysm may also extend into the common iliac arteries. Such aneurysms are typically brought on by the weakening of the arterial wall from vascular disease. Although abdominal aortic aneurysms often do not cause pain, unless treated, an aneurysm may rupture causing a fatal hemorrhage in a patient.
In the past aortic aneurysms were treated almost exclusively by surgical repair. Specifically, the aneurysm would be resected and replaced by an artificial artery known as a prosthetic graft. Because of the substantial risks associated with such an invasive surgery, however, other treatments for aortic aneurysms have been proposed including endovascular grafting.
Endovascular grafting involves the placement of a prosthetic graft within the lumen of the artery such that the graft spans the length of the aneurysm. In this manner the aneurysm can be excluded from the circulatory system rather than resected. Using a catheter as a deployment device, the endovascular graft can be introduced into the vascular system percutaneously. Once the graft has been positioned at the site of the aneurysm it can be attached to the vascular wall both above and below the aneurysm using expandable attachment devices to prevent movement of the graft after deployment.
To introduce an endovascular graft percutaneously, the graft must be collapsible into a small profile for negotiating the vascular system. Upon reaching the site of the aneurysm the graft and its attachment devices can be expanded into a desired shape using an inflating balloon catheter or other actuator. A variety of expandable attachment devices have been proposed for securing an endovascular graft to an interior wall of a vessel most of which use stents with hooks or barbs to penetrate the intima of the vessel. None of the proposed attachment devices, however, have been found to be ideally suited for use with an endovascular graft.
Accordingly an endovascular apparatus having a new expandable attachment device is desired. The new attachment device ideally should be small with a low profile and should expand to many times its initial diameter. It also should exert enough radial force when expanded to fix into the aorta and thereby reduce blood leaks around the apparatus.